This invention relates to a image processing device to implement a plurality of image processing functions simultaneously, especially relates to task scheduling of the plurality of image processing functions.
As both computer technology and picture technology have been drastically developed in recent years, it has become import to realize an image processing device to implement a plurality of image processing functions simultaneously. For instance, one image processing device with a camera which is installed on a automobile vehicle is requested to be capable of both discriminating a road lane and detecting an obstacle on the mad lane. When a computer implements a plurality of image processing function alone, it divides the image processing functions into a plurality of small processing functions each of which is called task and performs the tasks. In this case it is indispensable for the computer to manage every task involved without failure. In most cases of the image processing, the tasks are controlled in synchronization with the timing of the picture input. In the case of the image processing device installed on an automobile vehicle, the image processing is performed while pictures are being collected and the image processing function needs to be performed as soon as the image data to be processed is ready for processing after the image data is collected. In such an image processing system as explained above the image processing explained as above the interval for storing pictures is used for the interval for the task scheduling.
According to Japanese Laid-open Patent Application No. 06-67899, a frame to determine an interval for each task to start and the task scheduling is defined, the computer processing is performed in a frame defined on the task scheduling. To be specific, the frame for each computer function to be performed is controlled based on the task scheduling table consisting of frames whose interval is constant. If this method is applied to the image processing device, frames are defined by an interval at which synchronizing signals of pictures are given.
Japanese Laid-open Patent Application No. 2000-299841 discloses a method to identify picture data to be processed and define the timing for processing making use of picture synchronizing signal. In this method the scheduling is done for determining in which frame each video data is transmitted.